U.S. patent number 4,520,181 [Application Number 06/472,684] was granted by the patent office on 1985-05-28 for method for making a dicyclopentadiene thermoset polymer containig elastomer.
This patent grant is currently assigned to Hercules Incorporated. Invention is credited to Daniel W. Klosiewicz.
United States Patent |
4,520,181 |
Klosiewicz |
May 28, 1985 |
Method for making a dicyclopentadiene thermoset polymer containig
elastomer
Abstract
A method of making a thermoset polydicyclopentadiene by first
combining a plurality of reactant streams, one containing the
activator of a metathesis-catalyst system, a second containing the
catalyst of a metathesis-catalyst system and at least one
containing dicylopentadiene; then immediately injecting this
combination into a mold where polymerization results in the
formation of a tough, rigid thermoset polymer with high modulus and
excellent impact strength.
Inventors: |
Klosiewicz; Daniel W. (Newark,
DE) |
Assignee: |
Hercules Incorporated
(Wilmington, DE)
|
Family
ID: |
26993016 |
Appl.
No.: |
06/472,684 |
Filed: |
March 7, 1983 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
342453 |
Jan 25, 1982 |
4400340 |
|
|
|
Current U.S.
Class: |
525/247;
264/328.6; 525/290 |
Current CPC
Class: |
C08G
61/08 (20130101) |
Current International
Class: |
C08G
61/00 (20060101); C08G 61/08 (20060101); C08F
002/00 (); C08F 004/78 () |
Field of
Search: |
;264/328.6
;525/247,249,245 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Henderson; Christopher A.
Attorney, Agent or Firm: Lovercheck; Dale R.
Parent Case Text
This is a division of application Ser. No. 342,453, filed Jan. 25,
1982, and now U.S. Pat. No. 4,400,340.
Claims
What I claim and desire to protect by Letters Patent is:
1. A method of making a thermoset homopolymer comprising:
(a) combining a plurality of reactant streams, one of said streams
containing an activator of a metathesis-catalyst system, and
another of said streams containing a catalyst of a
metathesiscatalyst system, at least one of said streams containing
dicyclopentadiene, at least one of said streams containing
elastomer, whereby a reaction mixture is formed, said elastomer
being sufficient in amount to make the viscosity of said reaction
mixture between about 300 and about 1000 centipoises;
(b) immediately injecting said reaction mixture into a mold where
polymerization occurs, forming a thermoset dicyclopentadiene
homopolymer containing elastomer.
2. The method of claim 1 wherein said reaction mixture further
comprises a rate moderator.
Description
BACKGROUND OF THE INVENTION
This invention relates to a method for the preparation of a polymer
of dicyclopentadiene (hereinafter referred to as DCPD). In
particular, it relates to employing a metathesiscatalyst system to
form a high modulus, high impact strength thermoset poly(DCPD)
homopolymer. In a preferred embodiment the homopolymer is formed
when two solutions, one a catalyst/monomer mixture and the other an
activator/monomer mixture, are combined in a reaction injection
molding (hereinafter referred to as RIM) machine and then injected
into a mold.
Any good thermoset polymer should meet at least two criteria. It
should have desirable physical properties and it should lend itself
to easy synthesis and forming. Among the most desirable physical
properties for many polymers is a combination of high impact
strength and high modulus. A standard test for impact strength is
the notched Izod impact test, ATSM No. D-256. For an unreinforced
theremoset polymer to have good impact strength, its notched Izod
impact should be at least 1.5 ft. lb/in. notch. It is desirable
that this good impact strength be combined with a modulus of at
least about 150,000 psi at ambient temperature. Thermoset polymers
with high impact strength and high modulus find useful applications
as engineering plastics in such articles of manufacture as
automobiles, appliances and sports equipment. Among the critical
factors in the synthesis and forming of a thermoset polymer are the
conditions required to make the polymer set up or gel. Many
thermoset polymers require considerable time, elevated temperature
and pressure, or additional steps after the reactants are mixed
before the setting is complete.
While some references to poly(DCPD) have been made in the
literature, a thermoset homopolymer having high impact strength and
high modulus has never been described. Characteristics of thermoset
polymers include insolubility in common solvents such as gasoline,
naphtha, chlorinated hydrocarbons, and aromatics as well as
resistance to flow at elevated temperatures.
Work has been done on the metathesis copolymerization of DCPD with
one or more other monomers to produce soluble copolymers. This
copolymer formation has resulted in the production of unwanted
insoluble by-products. U.S. Pat. No. 4,002,815, for instance,
teaches the copolymerization of cyclopentene with DCPD, describes
an insoluble by-product and suggests that the by-product could be a
gel of a DCPD homopolymer.
Some work, usually in an attempt to produce soluble poly(DCPD's),
has been done on the metathesis homopolymerization of DCPD.
Japanese unexamined published patent applications KOKAI 53-92000
and 53-111399 disclose soluble poly(DCPD's). Several syntheses of
soluble poly(DCPD) have produced insoluble by-products. Takata et
al, J. Chem Soc. Japan Ind. Chem. Sect., 69, 711 (1966), discloses
the production of an insoluble poly(DCPD) by-product from the
Ziegler-Natta catalyzed polymerization of DCPD; Oshika et al,
Bulletin of the Chemical Society of Japan, discloses the production
of an insoluble polymer when DCPD is polymerized with WCl.sub.6,
AlEt.sub.3 /TiCl.sub.4 or AlEt.sub.3 /MoCl.sub.5 ; and Dall Asta et
al, Die Makromolecular Chemie 130, 153 (1969), discloses an
insoluble by-product produced when a WCl.sub.6 /AlEt.sub.2 Cl
catalyst system is used to form poly(DCPD).
In U.S. Pat. No. 3,627,739, a thermoset poly(DCPD) is the object of
synthesis. The poly(DCPD) of U.S. Pat. No. 3,627,739 is brittle,
having an Izod impact strength of only 0.78.
Not only is it desirable that the thermoset polymer have high
impact strength, but it is also desirable that it be easily
synthesized and formed. A RIM process achieves this second goal by
in-mold polymerization. The process involves the mixing of two or
more low viscosity reactive streams. The combined streams are then
injected into a mold where they quickly set up into a solid
infusible mass. RIM is especially suited for molding large
intricate objects rapidly and in low cost equipment. Because the
process requires only low pressures, the molds are inexpensive and
easily changed. Furthermore, since the initial materials have low
viscosity, massive extruders and molds are not necessary and energy
requirements are minimal compared to the injection molding or
compression molding commonly used. For a RIM system to be of use
with a particular polymer, certain requirements must be met:
(1) The individual streams must be stable and must have a
reasonable shelf-life under ambient conditions.
(2) It must be possible to mix the streams thoroughly without their
setting up in the mixing head.
(3) When injected into the mold, the materials must set up to a
solid system rapidly.
(4) Any additives-fillers, stabilizers, pigments, etc. must be
added before the material sets up. Therefore, the additives
selected must not interfere with the polymerization reaction.
It can be seen that when developing a RIM process a tradeoff must
be made. It is desirable that the polymer set up quickly, but the
polymerization cannot be too quick. The components cannot be so
reactive that they set up in the mixing head before they can be
injected into the mold. Once in the mold, however, the polymer
should set up as quickly as possible. It is not desirable that the
polymer take a long time or require additional steps to gel
completely.
It is known in the prior art to base a RIM system on the
combination of two reactive monomers, e.g., the polyol and the
diisocyanate monomers employed in a polyurethane system. It is
known, but not in the context of a RIM system, to combine two or
more reactive parts of a catalyst, where one or both are in
solution with the monomer, to form a homopolymer. A process which
employs two separate streams based on a two part catalyst system to
produce a thermoset polymer in such a manner that the streams can
be combined in one place and then rapidly set up in another is
unique and is a substantial contribution to the art. U.S. Pat. No.
2,846,426, Larson, claims the combination of two vapor streams, one
containing a vaporizable alkylaluminum compound and the other
containing a vaporizable compound of Group IV-B, V-B, or VI-B
metal, where at least one of the streams contains a gaseous
monomer. The vapor streams are combined and a thermoplastic polymer
is formed in the same reaction zone. U.S. Pat. No. 3,492,245,
Calderon et al, discloses the in-situ formation of a catalyst
system containing an organoaluminum compound, a tungsten hexahalide
and a hydroxy compound. Again, the reactive components are mixed
and the polymerization of an unsaturated alicyclic compound occurs
in the same vessel. U.S. Pat. No. 3,931,357, Meyer, teaches a
process for forming a soluble graft copolymer of a polydiene or a
polyalkenamer and an unsaturated polyolefin rubber which entails
combining a stream containing a metathesis catalyst component from
a metal of subgroups V through VII of the periodic table with a
stream containing an alkyl or a hydride of a metal from main groups
I through VII of the periodic table prior to the metathesis
reaction proper. Since the copolymer is soluble, there is no
requirement that it rapidly set up.
BRIEF DESCRIPTION OF THE INVENTION
This invention encompasses a method for producing a high impact
strength, high modulus thermost homopolymer comprising polymerized
units of DCPD by using a two part metathesiscatalyst system. The
DCPD polymer is a tough, rigid material with high modulus and
excellent impact strength. The flexural modulus is in the range of
about 150,000 to about 300,000 psi. and the notched Izod impact
strength is at least 1.5 ft. lb./in. notch.
The polymer can be synthesized by reacting DCPD with a two part
metathesis-catalyst system. The first part of the catalyst system
is comprised of a metathesis catalyst, preferably WOCl.sub.4,
WCl.sub.6 or a combination of WCl.sub.6 plus an alcohol or phenol.
The second part of the catalyst system is comprised of an activator
such as SnBu.sub.4, AlEt.sub.3, AlEt.sub.2 Cl, AlEtCl.sub.2, or
similar compounds. In a preferred synthesis, the activator is
Et.sub.2 AlCl. Also in the preferred synthesis the activator
containing solution includes an ester, ether, ketone or nitrile
which serves to moderate the rate of polymerization. Examples of
suitable moderators are ethyl benzoate and di-n-butyl ether. In a
preferred embodiment the two metathesis-catalyst system components,
plus the monomer, form the basis for at least two separate streams
which can be mixed in the head of a RIM machine and then injected
into a mold where they will quickly set up into a tough, infusible
mass. Various additives such as fillers and stabilizers can be
added to modify the properties of the thermoset polymer.
DETAILED DESCRIPTION OF THE INVENTION
Dicyclopentadiene can be polymerized in such a manner that the
resulting product is a thermoset homopolymer having high impact
strength and high modulus. The preferred monomer is commercially
available endo-DCPD (3a,4,7,7a-tetrahydro-4,7-methano-1H-idene).
The exo-isomer, while not commercially available, can be used just
as well. The preferred commercially available material normally has
a purity of 96-97%. Commercially available material should be
purified in order to prevent impurities from inhibiting the
polymerization. The low boiling fraction should be removed. This
can be done by stripping away several percent of the unsaturated
four to six carbon atom volatiles, i.e., the volatiles distilled
below 100.degree. C. at about 90.+-.3 torr. It is often desirable
to purify the starting material even further by treatment with
silica gel. Additionally, the water content of the starting
material should be below about 100 ppm. The presence of water
interferes with polymerization by hydrolysis of both the catalyst
and the activator components of the catalyst system. For example,
water can be removed by azeotropic distillation under reduced
pressure. Even after these steps the monomer still contains some
impurities. It should be understood, therefore, that throughout
this description the term homopolymer refers to the polymer
resulting from essentially pure starting material.
The homopolymerization of the purified DCPD is catalyzed by a two
part metathesis-catalyst system. One part contains a tungsten
containing catalyst, such as a tungsten halide or tungsten
oxhyalide, preferably WCl.sub.6 or WOCl.sub.4. The other part
contains an activator such as SnBu.sub.4 or an alkylaluminum
compound. The alkylaluminum compound can be an alkylaluminum
dihalide or dialkylaluminum halide where the alkyl group contains
one to ten carbon atoms. In the preferred activator the alkyl group
is ethyl with diethyl aluminum chloride being most preferred.
One part of the catalyst system comprises the tungsten containing
catalyst, as described above, preferably in solution with DCPD
monomer. The tungsten compound if unmodified, will rapidly
polymerize the monomer. Consequently, the tungsten compound should
first be suspended in a small amount of a suitable solvent. The
solvent must not be susceptible to halogenation by the tungsten
compound. Examples of preferred solvents are benzene, toluene,
chlorobenzene, dichlorobenzene, and trichlorobenzene. Sufficient
solvent should be added so that the tungsten compound concentration
is between about 0.1 to 0.7 mole per liter of solvent.
The tungsten compound can be solublized by the addition of a small
amount of an alcoholic or a phenolic compound. Phenolic compounds
are preferred. Suitable phenolic compounds include phenol,
alkyl-phenols, and halogenated phenols, with tert-butyl phenol,
tert-octyl phenol and nonyl phenol being most preferred. The
preferred molar ratio of tungsten compound/phenolic compound is
from about 1:1 to about 1:3. The tungsten compound/phenolic
compound solution can be made by adding the phenolic compound to a
tungsten compound/organic solvent slurry, stirring the solution and
then blowing a stream of a dry inert gas through the solution to
remove the hydrogen chloride which is formed. Alternatively, a
phenolic salt, such as a lithium or sodium phenoxide, can be added
to a tungsten compound/organic solvent slurry, the mixture stirred
until essentially all the tungsten compound is dissolved, and the
precipitated inorganic salt removed by filtration or
centrifugation. All of these steps should be carried out in the
absence of moisture and air to prevent deactivation of the
catalyst.
To prevent premature polymerization of the tungsten
compound/monomer solution, which would occur within a matter of
hours, from about 1 to about 5 moles of a Lewis base or a chelating
agent can be added per mole of tungsten compound. Preferred
chelants include acetylacetones, alkyl acetoacetates, where the
alkyl group contains from one to ten carbon atoms; preferred Lewis
bases are nitriles and ethers such as benzonitrile and
tetrahydrofuran. The improvement in the stability and shelf-life of
the tungsten compound/monomer solution is obtained whether the
complexing agent is added before or after the phenolic compound.
When purified DCPD is added to this catalyst solution it forms a
solution which is stable and has a shelf-life of several
months.
The other part of the metathesis-catalyst system comprises the
activator, as described above, preferably in DCPD monomer. This
mixture is storage stable and therefore, unlike the tungsten
compound/monomer solution, needs no additives to prolong its
shelf-life. If, however, an unmodified activator/monomer solution
is mixed with the catalyst/monomer solution, the polymerization
would initiate instantaneously and the polymer could set up in the
mixing head. The onset of polymerization can be delayed by adding a
moderator to the activator/monomer solution. Ethers, esters,
ketones and nitriles can act as moderators for the alkylaluminum
compounds. Isopropyl ether, di-n-butyl ether, ethyl benzoate,
phenylethyl acetate and diisopropyl ketone are preferred. Ethyl
benzoate and butyl ether are most preferred. The preferred ratio of
the alkylaluminum to moderator is from about 1:1.5 to about 1:5 on
a molar basis.
The polymerization time required for gelation is also temperature
dependent. As the temperature at which the reaction is carried out
is increased the reaction rate will also increase. For every eight
degree increase in temperature the reaction rate will approximately
double. Consequently, to keep the reaction rate controlled at
higher reaction temperatures a less active formulation of the
metathesiscatalyst system should be used.
What is ultimately required is that when the catalyst system's
components are combined, the resulting DCPD to tungsten compound
ratio will be from about 1,000:1 to about 15,000:1 on a molar
basis, preferably 2,000:1 and the DCPD to alkylaluminum ratio will
be from about 100:1 to about 2000:1 on a molar basis, preferably
about 200:1 to about 500:1. To illustrate a preferred combination:
sufficient DCPD is added to a 0.1 M tungsten containing catalyst
solution prepared as described above, so that the final tungsten
compound concentration is 0.007 molar. This corresponds to a DCPD
to tungsten compound ratio of 1000:1. Sufficient DCPD is added to
the Et.sub.2 AlCl solution, prepared as described above, so that
the alkylaluminum concentration is 0.048 M. This corresponds to a
DCPD to alkylaluminum ratio of 150:1. If these two streams are
mixed in a 1:1 ratio, the final ratio of DCPD to alkylaluminum will
be 300:1 and the final ratio of tungsten compound will be 2000:1
and the final ratio of DCPD to alkylaluminum will be 300:1 and the
final ratio of tungsten compound to alkylaluminum will be about
1:7. The illustrated combination is not the lowest catalyst level
at which moldings can be made, but it is a practical level that
provides for excess catalyst if impurities in the system consume
some of the catalyst components. A higher alkylaluminum level will
not only increase costs and residual chlorine levels but may result
in a less satisfactory cure. Too low a tungsten compound
concentration results in incomplete conversion. A wide range of
alkylaluminum activator to tungsten catalyst formulations produce
samples which have good out-of-mold properties such as tear
resistance, stiffness, residual odor, and surface properties.
In a preferred synthesis, the poly(DCPD) is made and molded with
the RIM process. The two parts of the metathesis-catalyst system
are each mixed with DCPD, to form stable solutions which are placed
in separates vessels. These containers provide the source for
separate streams. The two streams are combined in the RIM machine's
mixing head and then injected into a warm mold where they quickly
polymerize into a solid, infusible mass. The invention is not
intended to be limited to systems employing two streams each
containing monomer. It will be obvious to one skilled in the art
that there may be situations where it is desirable to have monomer
incorporated in just one stream or to employ more than two streams
where the additional streams contain monomer and/or additives.
These streams are completely compatible with conventional RIM
equipment. Metathesis-catalyzed polymerizations are known to be
inhibited by oxygen so it is necessary to store the components
under an inert gas but, surprisingly, it is not necessary to
blanket the mold with an inert gas. The streams are combined in the
mixing head of a RIM machine. Turbulent mixing is easy to achieve
because the process involves low molecular weight, rapidly
diffusing components. Typically the mixing heads have orifices
about 0.032 inch in diameter and a jet velocity of about 400
ft/sec. After being combined the mixture is injected into a mold
maintained at 35.degree.-100.degree. C., preferably
50.degree.-70.degree. C. The mold pressure is in the range of about
10-50 psi. A rapid exothermic reaction occurs as the poly(DCPD)
sets up. The mold can be opened in as little as 20-30 seconds after
the combined streams have been injected. In this short time heat
removal is not complete and the polymer is hot and flexible. The
polymer can be removed from the mold immediately while hot or after
cooling. After the polymer has cooled it will become a rigid solid.
The total cycle time may be as low as 0.5 minute. Post-curing is
desirable but not essential, to bring the samples to their final
stable dimensional states, to minimize residual odors, and to
improve final physical properties. Post-curing at about 175.degree.
C. for about 15 minutes is usually sufficient.
The product has a flexural modulus of about 150,000 to 300,000 psi
and a notched Izod impact resistance of at least about 1.5 ft.
lb/in. notch. The homopolymer is insoluble in common solvents such
as gasoline, naphthas, chlorinated hydrocarbons and aromatics,
resistant to flow at temperatures as high as 350.degree. C. and
readily releases from the mold.
Various additives can be included to modify the properties of
poly(DCPD). Possible additives include fillers, pigments,
antioxidants, light stabilizers and polymeric modifiers. Because of
the rapid polymerization time the additives must be incorporated
before the DCPD sets up in the mold. It is often desirable that the
additives be combined with one or both of the catalyst system's
streams before being injected into the mold. Fillers can also be
charged to the mold cavity, prior to charging the reaction streams,
if the fillers are such that the reaction stream can readily flow
around them to fill and the remaining void space in the mole. It is
essential that the additives not affect catalytic activity.
One class of possible additives is reinforcing agents or fillers.
These are compounds which can increase the polymer's flexural
modulus with only a small sacrifice in impact resistance. Possible
fillers include glass, wollastonite, mica, carbon black, talc, and
calcium carbonate. It is surprising that in spite of the highly
polar nature of their surfaces these fillers can be added without
appreciably affecting the polymerization rate. From about 5% to 75%
by weight may be incorporated. This and all subsequent percentages
are based on the weight of the final product. The addition of
fillers which have modified surface properties are particularly
advantageous. The exact amount of a particular filler to be used in
a particular situation will be easily determinable and will depend
on the preferences of the practitioner. The addition of fillers
also serves to decrease the mold shrinkage of the product. After a
short post cure at 150.degree.-200.degree. C. an unfilled product
will shrink from about 3.0 to about 3.5% whereas adding 20-25 wt %
filler will decrease the shrinkage to 1.5-2% and adding 33 wt %
filler will further decrease shrinkage to about 1%.
Since poly(DCPD) contains some unsaturation it may be subject to
oxidation. The product can be protected by the incorporation of as
much as about 2.0 wt % of a phenolic or amine antioxidant.
Preferred antioxidants include 2,6-tertbutyl-p-cresol,
N,N'-diphenyl-p-phenylene diamine and tetrakis
[methylene(3,5-di-t-butyl-4-hydroxy cinnamate)] methane. While the
antioxidant can be added to either or both streams, incorporation
into the activator/monomer stream is preferred.
The addition of a elastomer can increase the polymer's impact
strength 5-10 fold with only a slight decrease in flexural modulus.
The elastomer can be dissolved in either or both of the DCPD
streams in the 5-10 wt % range without causing an excessive
increase in the solution viscosity. Useful elastomers include
natural rubber, butyl rubber, polyisoprene, polybutadiene,
polyisobutylene, ethylenepropylene copolymer,
styrene-butadiene-styrene triblock rubber, styrene-isoprene-styrene
triblock rubber and ethylene-propylene diene terpolymers. The
amount of elastomer used is determined by its molecular weight and
is limited by the viscosity of the streams. The streams cannot be
so viscous that adequate mixing is not possible. The Brookfield
viscosity of DCPD is about 6 cps at 35.degree. C. Increasing the
viscosity to between about 300 cps and about 1000 cps alters the
mold filling characteristics of the combined streams. An increase
in viscosity reduces leakage from the mold and simplifies the use
of fillers by decreasing the settling rates of the solids. An
example of a preferred elastomer is styrene-butadiene styrene
triblock. Where 10 wt % of this additive is incorporated into the
streams not only is the viscosity increased to about 300 cps but
the impact strength of the final product also increases. Although
the elastomer can be dissolved in either one or both of the streams
it is desirable that it be dissolved in both. When the two streams
have similar viscosities more uniform mixing is obtained.
EXAMPLES 1 and 2
In Example 1 a 0.1 M solution of a tungsten containing catalyst
solution was prepared by adding 20 grams of WCl.sub.6 in 460 ml of
dry toluene under a N.sub.2 atmosphere and then adding a solution
of 8.2 grams of p-tert-butyl phenol in 30 ml of toluene. The
catalyst solution was sparged overnight with nitrogen to remove the
HCl generated by the reaction of WCl.sub.6 with the
p-tert-butylphenol. In this and in all the following examples
phenol is used as a shorthand for p-tert-butylphenol and for
simplicity the solution is referred to as WCl.sub.6 /phenol. Then a
0.033 M catalyst/monomer solution was prepared by mixing under
nitrogen 10 ml of DCPD, 0.07 ml of benzonitrile and 5 ml of the 0.1
M catalyst solution. An activator/monomer solution was prepared by
combining, under nitrogen, 8.6 ml of DCPD, 0.1 ml of isopropyl
ether and 0.36 ml of 1.0 M Et.sub.2 AlCl in DCPD.
Polymerization was accomplished by adding 1.1 ml of the 0.033 M
catalyst/monomer solution to 8.9 ml of the activator/monomer
solution. Both solutions were intially at 25.degree. C. They were
vigorously mixed. After a brief induction period and a sharp
exotherm was observed. A solid, insoluble polymer was formed. The
time that elapsed until rapid polymerization began and the total
exotherm of the sample above the starting temperature are shown in
Table I.
In Example 2 the above procedure was repeated except that 0.36 ml
of 1.0 M EtAlCl.sub.2 was used in place of Et.sub.2 AlCl to prepare
the activator solution and the reaction was started at 40.degree.
C. A solid, insoluble polymer was formed. The results are shown in
Table I.
TABLE I ______________________________________ Example 1 Example 2
______________________________________ DCPD 72 mmol 72 mmol
WCl.sub.6 /Phenol 0.036 mmol 0.036 mmol Et.sub.2 AlCl 0.36 mmol --
EtAlCl.sub.2 -- 0.36 mmol Benzonitrile 0.04 mmol 0.04 mmol
Isopropyl ether 0.72 mmol 0.72 mmol Initial Temperature 25.degree.
C. 40.degree. C. Time until exotherm 15 sec. 445 sec. Exotherm
122.degree. C. 147.degree. C.
______________________________________
EXAMPLES 3-8
In Examples 3 through 8 the procedure described in Example 1 was
repeated except that different moderators were added to the
activator/monomer solution. In each example the ratio of moles
moderator to moles of Et.sub.2 AlCl was held constant at 2:1. In
example 3, di-n-butyl ether was added while in Example 4,
diisopropyl ether was used. In Example 5, ethyl benzoate was used
while in Example 6, phenylethyl acetate was added. In Example 7,
diisopropyl ketone was added. Lastly, in Example 8, tetrahydrofuran
was added. In each example the initial temperature was 25.degree.
C. (.+-.1.degree. C.). Example 8 was the only case where a solid
insoluble polymer was not obtained. The results are listed in Table
II.
TABLE II
__________________________________________________________________________
Example 3 Example 4 Example 5 Example 6 Example 7 Example 8
__________________________________________________________________________
DCPD 72 mmol 72 mmol 72 mmol 72 mmol 72 mmol 72 mmol WCl.sub.6
/Phenol 0.036 mmol 0.036 mmol 0.036 mmol 0.036 mmol 0.036 mmol
0.036 mmol Et.sub.2 AlCl 0.36 mmol 0.36 mmol 0.36 mmol 0.36 mmol
0.36 mmol 0.36 mmol Di-n-butyl ether 0.72 mmol -- -- -- -- --
Diisopropyl ether -- 0.72 mmol -- -- -- -- Ethyl benzoate -- --
0.72 mmol -- -- -- Phenyl ethyl acetate -- -- -- 0.72 mmol -- --
Diisopropyl ketone -- -- -- -- 0.72 mmol -- Tetrahydrofuran -- --
-- -- -- 0.72 mmol Benzonitrile 0.04 mmol 0.04 mmol 0.04 mmol 0.04
mmol 0.04 mmol 0.04 mmol Time until Exotherm 42 sec. 15 sec. 60
sec. 282 sec. 160 sec. no rxn. Exotherm 153.degree. C. 122.degree.
C. 155.degree. C. 157.degree. C. 147.degree. C. --
__________________________________________________________________________
EXAMPLES 9-12
In Examples 9 through 12 the activator to catalyst ratios were
varied. In Example 9, 0.88 ml of catalyst/monomer solution,
described in Example 1 was added to 7.1 ml of DCPD containing
sufficient Et.sub.2 AlCl and di-n-butyl ether to give the
composition listed in Table III. In Example 10, 0.44 ml of the same
catalyst/monomer solution as used in Example 9 was added to 7.5 ml
of the same activator/monomer solution used in Example 9, to give
the final composition listed in Table III. In Example 11, 4.0 ml of
a catalyst/monomer solution prepared by mixing 20 ml of DCPD with
1.5 ml of a 0.1 M WCl.sub.6 /phenol solution, was mixed with 4.0 ml
of an activator/monomer solution. In this activator solution there
was sufficient Et.sub.2 AlCl to give a DCPD to alkylaluminum ratio
of 100:1 and sufficient di-n-butyl ether to give a di-n-butyl ether
to aluminum ratio of 2:1. In Example 12, 4.0 ml of the
catalyst/monomer solution used in Example 11 was mixed with 2.0 ml
of DCPD and 2.0 ml of the activator/monomer solution used in
Example 11. In each case a solid, insoluble polymer was formed. The
results of these reactions showing a variation in the exotherms due
to variations in the Al/W ratio, are listed in Table III.
TABLE III ______________________________________ Example 9 Example
10 Example 11 Example 12 ______________________________________
DCPD 57.6 mmol 57.6 mmol 57.6 mmol 57.6 mmol WCl.sub.6 /Phenol
0.029 mmol 0.0145 mmol 0.029 mmol 0.029 mmol Et.sub.2 AlCl 0.29
mmol 0.29 mmol 0.29 mmol 0.145 mmol Di-n-butyl 0.58 mmol 0.58 mmol
0.58 mmol 0.29 mmol ether Benzonitrile 0.033 mmol 0.016 mmol 0.033
mmol 0.033 mmol DCPD/Al 200 200 200 400 DCPD/W 2000 4000 2000 2000
Al/W 10/1 20/1 10/1 5/1 Time to 50 sec. 48 sec. 33 sec. 43 sec.
Exotherm Exotherm 153.degree. C. 120.degree. C. 145.degree. C.
168.degree. C. ______________________________________
EXAMPLES 13-15
In Examples 14-15 a small amount of a polar material was added to
the catalyst/monomer solution in order to illustrate the effect of
polar material on shelf-life. In Example 13, a catalyst/monomer
solution was prepared by adding 2.0 ml of a 0.1 M tungsten
containing catalyst solution, as described in Example 1, to 20 ml
of DCPD in a nitrogen purged tube. This mixture gelled to a
non-flowing material within 24 hours. In Example 14, the same
procedure was carried out except that 0.03 ml of benzonitrile was
added, giving a final benzonitrile to tungsten halide ratio of
1.5:1. This mixture did not gel and was catalytically active after
4 weeks. Example 15 illustrates the result when tetrahydrofuran was
added to give a tetrahydrofuran to tungsten halide ratio of 1.5:1.
Again, a greatly improved storage stability was observed. The
results are listed in Table IV.
TABLE IV ______________________________________ Example 13 Example
14 Example 15 ______________________________________ DCPD 130 mmol
130 mmol 130 mmol WCl.sub.6 /Phenol 0.2 mmol 0.2 mmol 0.2 mmol
Benzonitrile -- 0.3 mmol -- Tetrahydrofuran -- -- 0.3 mmol
Condition after gelled low viscosity low viscosity 24 hours
Condition after gelled low viscosity low viscosity 4 weeks Activity
after gelled acceptable acceptable 4 weeks
______________________________________
EXAMPLES 16-18
In Examples 16-18, the concentration of di-n-butyl ether
incorporated into the activator/monomer solution to serve as a
moderator was varied. In Example 16, the procedure used in Example
1, was followed with the exception that 0.078 ml of n-butyl ether
was substituted for the diisopropyl ether. This gave a final ratio
of di-n-butyl ether to alkylaluminum of 1.5:1. In Example 17, the
procedure was repeated except that 0.156 ml of di-n-butyl ether was
added, giving a final ether/Al ratio of 3:1. In Example 18,
sufficient di-n-butyl ether was added to bring the final ether to
alkylaluminum ratio to 5:1. All the reactions in Table V were
initiated at 25.degree. C. In each case a solid, insoluble polymer
was formed. The results of the reactions are listed in Table V.
TABLE V ______________________________________ Example 16 Example
17 Example 18 ______________________________________ DCPD 57.6 mmol
57.6 mmol 57.6 mmol WCl.sub.6 /Phenol 0.029 mmol 0.029 mmol 0.029
mmol Et.sub.2 AlCl 0.29 mmol 0.29 mmol 0.29 mmol Di-n-butyl ether
0.43 mmol 0.86 mmol 1.45 mmol Benzonitrile 0.033 mmol 0.033 mmol
0.033 mmol Ether/Al 1.5 3.0 5.0 Elapsed time 36 sec. 55 sec. 75
sec. until exotherm Exotherm 150.degree. C. 158.degree. C.
159.degree. C. ______________________________________
EXAMPLES 19-21
In Examples 19-21, the level of Et.sub.2 AlCl used in the
polymerization of DCPD was varied. In Example 19, 18.5 ml of DCPD
was mixed under N.sub.2 with 1.5 ml of a 1.0 M solution of Et.sub.2
AlCl in DCPD and with 0.55 ml of di-n-butyl ether. Then in a
N.sub.2 purged tube 8.9 ml of this activator/monomer solution was
mixed with 1.1 ml of a catalyst/monomer solution as described in
Example 1. In Example 20, 4.5 ml of the activator/monomer solution
used in Example 19 was combined with 4.4 ml of DCPD and 1.1 ml of
the catalyst/monomer solution used in Example 20. In Example 21,
2.5 ml of the activator/monomer solution used in Example 19 was
combined under N.sub.2 with 6.4 ml of DCPD and 1.1 ml of the
catalyst/monomer solution used in Example 19. The final
compositions of these reaction mixtures are listed in Table VI. All
reactions were initiated at 25.degree. C.
TABLE VI ______________________________________ Example 19 Example
20 Example 21 ______________________________________ DCPD 72 mmol
72 mmol 72 mmol WCl.sub.6 /Phenol 0.036 mmol 0.036 mmol 0.036 mmol
Et.sub.2 AlCl 0.72 mmol 0.36 mmol 0.20 mmol Di-n-butyl ether 1.44
mmol 0.72 mmol 0.40 mmol Benzonitrile 0.04 mmol 0.04 mmol 0.04 mmol
DCPD/Al 100 200 360 Di-n-butyl 2/1 2/1 2/1 ether/Al Elapsed time 40
sec. 55 sec. 144 sec. until exotherm Exotherm 150.degree. C.
151.degree. C. 145.degree. C.
______________________________________
EXAMPLES 22-25
The effect of impurities on the catalyst system is illustrated in
Examples 22 through 25. In Example 22, a 0.007 M solution of
WCl.sub.6 /phenol in DCPD was prepared by mixing under nitrogen 150
ml of DCPD with 10.8 ml of a 0.1 M WCl.sub.6 /phenol solution in
toluene and 0.11 ml of benzonitrile. Then 3.0 ml of this solution
was mixed under nitrogen with 3 ml of a DCPD solution containing
AlEt.sub.2 Cl at a level DCPD to alkylaluminum of 150:1 and
di-n-butyl ether at a level of ether to alkylaluminum of 1.5:1.
In Example 23, a 10 ml sample of the catalyst/monomer solution used
in Example 22 was mixed with a impurity, 0.036 mmol of H.sub.2 O,
added as a dispersion in DCPD. One and one-half hours later, 3 ml
of this mixture was mixed under nitrogen with 3.01 of the
activator/monomer solution described in Example 22. The reaction
was repeated this time combining the activator/monomer solution
with the catalyst/monomer solution 18 hours after the H.sub.2 O had
been added.
Example 24 was done in the same manner as Example 23 with the
exception that 0.036 mmol of tert-butyl hydroperoxide was added to
a second 10 ml sample of the catalyst solution rather than H.sub.2
O. The reactivity of the resultant mixture was checked 11/2 and 18
hours after the addition of the impurity. Example 25 was carried
out in the same manner with the exception that 0.072 mmol of
di-tert-butylperoxide was the impurity added initially to 10 ml
sample of the catalyst/monomer solution. In every case a solid,
insoluble polymer was formed.
TABLE VII ______________________________________ Example 22 Example
23 Example 24 Example 25 ______________________________________
DCPD 43 mmol 43 mmol 43 mmol 43 mmol WCl.sub.6 /Phenol 0.021 mmol
0.021 mmol 0.021 mmol 0.021 mmol H.sub.2 O -- 0.01 mmol -- --
tert-butyl- -- -- 0.01 mmol -- hydroperoxide Di-tert-butyl- -- --
-- 0.02 mmol peroxide Et.sub.2 AlCl 0.14 mmol 0.14 mmol 0.14 mmol
0.14 mmol Added 0 0.5/1 0.5/1 1/1 Impurity/W Induction 31 sec. 50
sec. 98 sec. 33 sec. Time after 11/2 hrs. Exotherm 173.degree. C.
171.degree. C. 168.degree. C. 171.degree. C. after 11/2 hrs.
Induction 36 sec. 98 sec. 266 sec. 73 sec. time after 24 hrs.
Exotherm 170.degree. C. 170.degree. C. 155.degree. C. 169.degree.
C. after 24 hrs. ______________________________________
EXAMPLES 26-33
Samples of polymerized DCPD were made by RIM processing using a
standard RIM machine supplied by Accuratio Co. of Jeffersonville,
Indiana. The following description illustrates the standard
procedure for molding samples. First the desired amount of DCPD was
charged into two 2 gallon tanks. The tanks are located on different
sides of the RIM machine: the tank on the A side is the one to
which the activator was later added and the tank on the B side is,
the one to which the catalyst was later added. If desired, rubber
and/or organic resins were added as a predissolved solution in
DCPD. Also solid fillers, if desired, were added.
The tanks were then closed off and inerted with nitrogen.
Sufficient Et.sub.2 AlCl was transferred into the A tank to bring
the alkylaluminum concentration to 0.048 M and sufficient
di-n-butyl ether was added to achieve an ether to alkylaluminum
ratio of 1.5:1. Next, sufficient WCl.sub.6 /phenol to bring the
concentration of the catalyst in the B side to 0.007 M was added to
the B tank. The catalyst was added as a 0.1 M solution in toluene.
All transfers were done in a way to preclude the entrance of oxygen
or moisture into the system. The materials were then thoroughly
blended in their respective tanks.
The mixing of the A stream and the B stream was accomplished using
a standard impingement type RIM mixhead. The ratio of the
activator/monomer solution mixed with catalyst/monomer solution was
1:1. The impingement mixing was accomplished by passing both the
solutions through orifices 0.032" in diameter at a flow rate
approximately 80 ml/sec. This required pumping pressure of
approximately 1000 psi.
The resulting mixture flowed directly into a mold heated between
50.degree. C. and 60.degree. C. The mold was made out of aluminium
and was chrome plated. The mold had a flat cavity which formed a
plaque sample 10".times.10".times.1/8" thick. A clamping force of
1.5 tons was used to keep the mold closed. The finished samples
were removed at various times after mold filling ended.
In Example 26, the outlined molding procedure was followed where
there was added 10 wt % added styrene-butadienestyrene rubber
(Kraton no. 1102 manufactured by Shell Chemical Co). The sample was
removed from the mold after 2 minutes. In Example 27 a material of
the same composition as Example 26 was produced. This time mold was
opened 30 seconds after the combined streams were injected. The
surface features of Example 27 were noticably better than those of
Example 26. In Examples 28, 10 wt % of a thermally polymerized
dicyclopentadiene resin was added in addition to both the
catalyst/monomer and the activator/monomer solutions in addition to
the styrene-butadiene-styrene rubber.
Various inorganic fillers were incorporated into the DCPD polymer
by adding equal amounts to both the catalyst/monomer and the
activator/monomer solutions. In Example 29, samples were made
containing 33 wt % 1/8" milled glass (P117B grade of Owens Corning
Co.). These samples were made by initially slurrying the glass into
both solutions the catalyst/monomer and the activator/monomer
otherwise, these solutions were indentical to those used in Example
28. In Example 30 a composition consisting of 10 wt % wollastonite
was made by adding the filler to a formulation identical to that
described in Example 28. In Example 31 the same procedure was
followed as in Example 30 except that a 33 wt % level of
wollastonite was employed. In Example 32, 25 wt % wollastonite was
added to formulation described in Example 27. In each case a solid,
insoluble polymer is formed. Representative properties of Examples
26-32 are listed in Table VII.
Example 33 is a RIM processed poly(DCPD) made without any rubber
additives.
TABLE VIII
__________________________________________________________________________
Example Example Example 26 Example 27 Example 28 Example 29 Example
30 31 Example 33
__________________________________________________________________________
Resin Composition % cyclopentadiene resin -- -- 10 10 10 10 -- -- %
Kraton 1102 10 10 10 10 10 10 10 -- % DCPD 90 90 80 80 80 80 90 100
Filler Composition wt % 1/8" milled glass -- -- -- 33 -- -- -- --
wt % wollastonile -- -- -- -- 10 33 25 -- Tensile Properties
Strength (psi) -- 4,860 5,230 -- 4,700 -- 4,290 5,050 Modulus (psi)
-- 262,000 257,000 -- 426,000.sup.1 -- 683,000.sup.1 270,000
Elongation at yield (%) -- 4.0 4.0 -- 3.0 -- 2.0 3.4 Flexural
Properties Strength (psi) 7,400 8,600 -- 8,200 9,000 8,400 8,300
8,400 Modulus (psi) 235,000 250,000 -- 526,000.sup.2 390,000.sup.2
670,000.sup.2 480,000.sup.2 270,000 Impact Properties Notched Izod
(ft #/in. notch) 13.2 10.5 11.0 2.7 2.0 2.9 -- 2.3 Plate Impact at
5000"/min. (ft. #) 23.degree. C. 21.0 -- -- -- 11.2 -- 11.3 --
0.degree. C. 15.7 -- -- -- 12.0 -- 11.8 -- -20.degree. C. 12.3 --
-- -- 11.9 -- 12.7 -- Heat Deflection Temperature -- .sup.
65.degree. .sup. 64.degree. .sup. 81.degree. .sup. 69.degree. --
.sup. 79.degree. 60.degree. at 264 psi (.degree.C.) Coefficient of
Thermal -- 6.0 .times. -- 3.2 .times. 5.2 .times. 10.sup.-5 -- 3.8
--imes. 10.sup.- Expansion (in/in .degree.F.).sup.2 10.sup.-5
10.sup.-5 Linear Mold Shrinkage.sup.2 (%) 2.6 3.5 3.1 1.0 1.6 1.0
1.5 --
__________________________________________________________________________
.sup.1 Value in the direction parallel to the direction of flow.
.sup.2 Value is the average of the values obtained perpendicular to
the direction of flow and parallel to the direction of flow.
* * * * *